Chem 109 - General Chemistry - Spring 2011

Lecture Notes 17: 28 February

Return Exam 1 - Key and Distribution posted on Moodle

Thermochemistry

Energy

Law of Conservation of Energy

Energy can be transformed, but is neither created nor destroyed in chemical processes. Thus radiant energy can be transformed into heat which may to used to expand the volume of a gas and vice versa, bond energy can be converted into heat and/or light, etc.

Problem here of course is- What is energy? Energy is the capacity to do work. So what's work? Work occurs when an object (mass) is moved against a force. Some common forms of energy important to our study include:

Kinetic Energy (KE) - energy due to motion. KE = 1/2 mv².
Potential Energy (PE) - energy due to position. In chemical systems we also say it is due to composition, though ultimately this reduces to positions of atoms and electrons relative to each other.

Syllabus / Schedule